They have discovered a 'lost valley' containing mysterious cities that were built thousands of years ago. A large network of ancient cities that have been lost for thousands of years has been found in the Amazon using laser technology. Archaeologists mapping the Upano region in eastern Ecuador have discovered a group of interconnected mysterious cities.

The cities were connected by a network of roads and canals that were considered very 'sophisticated' in their time. Research shows that these cities emerged between 1,500 and 3,000 years ago before suddenly disappearing.

The researchers, who first reported this finding in the journal Science on Thursday, estimated that the cities were inhabited by at least 10,000 people. The population of the lost cities in the Amazon valley is equivalent to that of England during the Roman Empire era. "This is a lost city valley, truly extraordinary," said Professor Stéphen Rostain, director of investigation at the National Scientific Research Center, France.

This site is apparently located beneath a volcano, which may have caused the destruction of the city and its inhabitants. However, research has also found evidence of threats from foreign residents to the cities inhabited by the Upano people between 500 BC and 300 to 600 AD.

Some ditches that block the entrance to the city indicate that these cities are used as defenses against threats from foreign populations around them.

Initially, this archaeologist was reminded not to investigate the area because it was believed that there were no ancient civilizations that ever inhabited the Amazon forest. The problem is, until now, ancient cities have only been found in the highlands of South America, including Machu Picchu in Peru. Previous researchers believed that only a small number of nomadic people lived in the Amazon until Christopher Columbus reached America in the 15th century.

The researchers also found that the site was surrounded by agricultural fields and that the surrounding roads were equipped with bridges and ditches dug on both sides, which they believed to be drainage channels used to manage water in the area.